Build upon URL rather than PSL

[annevk]

Instead of "parsing" the Public Suffix List directly, use new terminology from the URL Standard.

Fixes #3711.

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/infrastructure.html ( diff )
/origin.html ( diff )
/references.html ( diff )

[annevk]

@mikewest what do you think?

It might be worth trying to take this further and remove "is a registrable domain suffix of or is equal to", but that'll require changes to WebAuthn.

[annevk]

(Note: this relies upon landing whatwg/url#391 first.)

[mikewest]

I do think it's simpler if we could just remove "is a registrable domain suffix of or is equal to" entirely, as it isn't providing much value if it's just wrapping "same site" with a host parser. It seems like WebAuthn could do that directly, and it would end up being clearer: @equalsJeffH, WDYT?

[mikewest]

LGTM. Happy to have the broader discussion about whether to keep the algorithm at all in a separate bug if you prefer to land this as-is.

[annevk]

Hmm, this is wrong. The problem is that on x.example.com you can use example.com, but you cannot use y.x.example.com. So I guess we need some kind of public suffix check here.

[mikewest]

Oh. Ha. You're entirely correct. I should have thought about this more deeply before hitting the "yes!" button. :(

[annevk]

I gave this another shot. I think it's correct now.

[annevk]

@mikewest could you take another look? Would be nice to know if the primitives in URL actually work.

[mikewest]

I think this does look correct now. Thanks for taking another pass, and sorry I missed it the first time around. One optional nit that might clarify things, but otherwise LGTM.

[mikewest]

Optional nit: It might make this clearer if you stick with comparing |host| with its public suffix, rather than checking that its registrable domain is null (as the latter requires more knowledge of how URL actually works).